MICROCONTROLLER BASED RESISTANCE MEASURING DEVICE

Abstract

Resistance is a very important term as far as electricity is concerned. And so is the importance of the measurement of resistance. Measurement of resistance is much more of an importance as part of a bigger project like touch screens using resistive method, Contact detector, etc than as an individual project. So it is very logical to do a mini-project on the resistance measurement and learn how to apply it to accomplish various complex tasks. The resistance measurement device is a device that can be used to measure the resistance that is placed between the two leads of the device. The system is fully controlled by the 8 bit microcontroller ATmega328P which has 32 Kbytes of flash memory where the program is stored and 2Kbytes of RAM. A simple electronic circuit with two resistance connected in series is used. One of the resistances is kept as a base reference resistor and the second resistor is assumed to be the variable unknown resistance. A constant voltage of +5v is dropped on the two resistances and by analysis of the voltage drop ratios the unknown resistance value is calculated. The result is displayed on computer. Also the resistance measurement is done only when the user asks the device to do so through the computer serial communication port.